From the Japanese Patent Application Publ. No. 2002-367263 a loading controller for a loading device of an optical disk recording and reproducing device is known, which controller is constituted to move a disk tray of the loading device by impressing a driving voltage to a disk tray motor. In order to eliminate the need for an end-switch to switch off the driving voltage impressed to the disk tray motor at an end position of the disk tray, the driving voltage is impressed to the disk tray motor for a time period which exceeds the time period for the disk tray to be moved from an open position to a closed position or from the closed position to the open position by a predefined amount of time. The controller monitors the driving voltage or the driving current of the disk tray motor after starting, and when the current value exceeds a prescribed value or when the driving voltage falls below a prescribed value the controller assumes that the disk tray has reached the open position or the closed position. This prescribed value can be calibrated by pulling in the tray for a fixed time. After the time expired the value can be measured.
With the known device, however, it has proved to be a disadvantage that detection of an end position of the disk tray based on measuring the driving current or voltage and comparing it with an upper limit value or a lower limit value, respectively, disregards the fact that exceeding the upper limit or falling below the lower limit is possibly not due to stopping rotation of the motor when the disk tray has reached its end position, but may also be put down to blocking the disk tray during its travel between said end positions. There are no means provided to detect an absolute position of the disk tray.